I find even the best AI is still too stupid to rely on. Better to have complete control then to give the AI any chance to mess it up. I don't find it frustrating to micro manage all actions; I find it frustrating when stupid AI messes up my plans. As for dexterity and coordination, I don't think RTwP games are where this is really required, such as it is with sport games and something like GoW; but to that point, I don't want to spend my time developing physical skills for something ephemeral like a game. If you're going to put the time in practicing and learning such skills, better to learn how to strum some chords. It will be with you your whole life.
That really illustrates my point - that not enough attention is paid by developers to how players interact with their games. I completely agree that most AI sucks. The best I can remember is DA:O, which allowed you to define detailed rules for each companion's behaviour, and had a very good UI for defining rules, as well as trivially prioritising rules and turning them on/off. But that was very much an exception, and probably represents the apogee of Bioware's design in this regard.
And no, I also agree RPGs are not twitch gaming, but the apparent difficulty detractors of RTwP have with the act of pausing led me to conclude that it must be some player control problem.
Perhaps a better way to consider things is what players WANT out of a control mechanism.
Players who express a strong preference for TB seem ( on the whole ) to stress a desire to direct all activities in detail. While such micro-management is possible in a typical RTwP game, in most it is undoubtedly clunky to do so, and therefore frustrating.
Conversely, those that express a strong preference for RTwP seem ( on the whole ) to stress a desire for fluidity without detailed management. While it is possible for a typical TB game to automate control, most do not do so, also leading to frustration.
It is entirely possible, under both control schemes, to consider and try to acommodate ( as much as possible ) a variety of player preferences. Larian;s games do try to generate the illusion of urgency/action during TB combat through active/exciting music and animations, but there is a limit to what you can achieve with that when very little is actually happening. Similarly, you could consider the choice to use party initiative and allow simultaneous turns for co-op to be an attempt to inject more fluidity in MP. For SP, improved fluidity would need AI to automate party companions. This is not evident in BG3 at the moment, but may be there at release if the issue is considered important enough.